Recent advances in breast cancer treatment include the advent of aromatase inhibitors (AIs) in the adjuvant setting with better efficacy and toxicity profiles than tamoxifen. However, AIs generally do not improve lipid profile as tamoxifen does, and there has been suggestion of increased cardiovascular risk with AI use. This has become an area of concern, particularly in light of the view that tamoxifen may protect against cardiovascular disease. This review of the current literature and updated trial data examines the effect both AIs and tamoxifen have on lipids and cardiovascular risk. It also highlights the importance of interpreting such data within the larger context of cardiovascular health in postmenopausal women.